Golf club head

ABSTRACT

A golf club head having a matrix layer composed of an interconnected reinforcement structure and a polymer material is disclosed herein. The matrix layer provides the golf club head with a greater coefficient of restitution during impact with a golf ball. The matrix layer is preferably disposed within a recess in the front wall of the body of the golf club head. The interconnected reinforcement structure is preferably composed of interconnected hexagonal cells.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 10/249,715, filed on May 2, 2003, now U.S. Pat. No.6,932,716, which is a continuation-in-part application of U.S. patentapplication Ser. No. 10/063,680, filed on May 7, 2002, now U.S. Pat. No.6,607,451, issued Aug. 19, 2003, which is a continuation application ofU.S. patent application Ser. No. 09/551,284, filed on Apr. 18, 2000, nowU.S. Pat. No. 6,390,932, issued May 21, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a golf club head. More specifically,the present invention relates to a golf club head with a polymer face.

2. Description of the Related Art

Technical innovation in the material, construction and performance ofgolf clubs has resulted in a variety of new products. The advent ofmetals as a structural material has largely replaced natural wood forwood-type golf club heads, and is but one example of this technicalinnovation resulting in a major change in the golf industry. Inconjunction with such major changes are smaller scale refinements tolikewise achieve dramatic results in golf club performance. For example,the metals comprising the structural elements of a golf club head havedistinct requirements according to location in the golf club head. Asole or bottom section of the golf club head should be capable ofwithstanding high frictional forces for contacting the ground. A crownor top section should be lightweight to maintain a low center ofgravity. A front or face of the golf club head should exhibit highstrength and durability to withstand repeated impact with a golf ball.While various metals and composites are known for use in the face,several problems arise from the use of traditional face structure andmaterials. In addition, material interaction of the golf club head andthe golf ball during impact is an important factor for performance ofthe golf club.

The golf ball is typically composed of a core-shell arrangement with athin polymer shell, or cover material such as ionomers, surrounding arubber-like core. These polymeric materials exhibit compression andshear, stiffness and strength properties dependent upon strain (load),input frequency (time dependency of small linear strain), strain rate(time rate of loading including large nonlinear strains), andtemperature. The compression and shear stiffness properties of polymericmaterials are measured and classified in terms of a storage moduli (E′,G′) and a loss moduli (E″, G″), respectively. The storage moduli (E′,G′) represent the amount of compression and shear energy, respectively,stored during a complete loading cycle. For quasi-static loading, it isequivalent to the well known Young's modulus (E′=E) and shear modulus(G′=G=E/(2(1+v)), where (v) is the material Poisson ratio. For mostpolymers, the storage modulus increases significantly with strain, inputfrequency, and strain rate. For example, typical storage moduli for golfballs at low speed impacts, in the temperature range (50–100° F.), areE′_(ball)=450–6,000 lb/in² and G′_(ball)=150–2,000 lb/in². Duringhigh-speed impacts, in the temperature range (50–100° F.), the typicalstorage moduli are E′_(ball)=9,000–50,000 lb/in² andG′_(ball)=3,000–16,500 lb/in². The low speed impact represents a puttingstroke or a soft pitch shot, while the high-speed impact represents agolf swing with an iron-type or a wood-type golf club head.

The loss moduli (E″, G″) represent the amount of compression and shearenergy, respectively, dissipated during a cycle. For most polymers, theloss moduli also increase significantly with strain, input frequency,and strain rate, but the rate of increase can be very different than theaforementioned storage moduli. Finally, the magnitude of the loss moduliat a given strain, strain rate, frequency, or temperature typically varyfrom 0.005–2.0 times that of the storage moduli.

A loss (or damping) factor (η_(E), η_(G)) or loss angle (δ_(E), δ_(G))for compression and shear are commonly defined as the ratio of thecorresponding moduli;

${\eta_{E} = {{{Tan}\;\delta_{E}} = \frac{E^{''}}{E^{\prime}}}},\mspace{14mu}{\eta_{G} = {{{Tan}\;\delta_{G}} = {\frac{G^{''}}{G^{\prime}}.}}}$

These loss factors are an important measure of the damping capability(energy loss mechanisms) of the material. For most ball-type materials,(η_(E)≅η_(G)) and magnitudes fall in the range of 0.005 (low energyloss) to 2.0 (high-energy losses), where magnitudes clearly depend uponpolymer composition, strain, input frequency, strain rate, andtemperature. As a comparison, the loss factors (energy loss mechanisms)in a metallic face of a golf club head are on the order of 10–100 timessmaller than that of a golf ball. For most elastomeric polymer materialsoperating below the glass transition region, the Poisson ratio is fairlyconstant with (v=0.4–0.5), while for stiff polymers acting at or abovethe glass transition region (v=0.3–0.33).

Thus, during impact of the golf ball with the golf club head, asignificant portion of impact energy is lost as a result of the largedeformations (0.05 to 0.50 inches) and deformation rates of the highdamped golf ball materials, as opposed to the small deformations of thelow damped metallic club face (0.025 to 0.050 inches) materials. Alarger portion of this impact energy is lost in the golf ball becausethe magnitude of the deformation, the deformation rate, and energy lossmechanisms are greater for the golf ball than the face of the golf clubhead.

Application of hard polymers to the face of the golf club headrepresents a traditional structure of natural wood golf club heads,where a hard insert material centrally located in the face of the golfclub and requiring an exacting fit between two or more distinctelements. The hard insert must be manufactured to a close tolerance tofit within a recess in the face of the golf club, and high surfacehardness is less efficient in transferring energy to the golf ballduring impact with the golf club. A homogeneous face structure issimpler to manufacture but is limited to the inherent materialproperties of the single material comprising the face structure. Thepresent invention achieves a more efficient energy transfer duringimpact while maintaining a simple construction.

The use of a polymer coating or layer on the face of a metal driver hasbeen shown to increase durability and the coefficient of restitution(“COR”) of the driver through the compliance of the polymer layer.However, when a golf ball impacts the face at angles that are not normalto face, such as the case with lofted drivers, shear deformation of thepolymer coating introduces energy losses that reduce or eliminate theCOR benefit provided by the polymer coating.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a solution to the shear deformation of apolymer layer during non-normal angle impact of a golf ball with apolymer coated or polymer layer face. The present invention is a golfclub head with a matrix layer disposed on the face. The matrix layer ispreferably composed of a reinforcement structure and a polymer material.The reinforcement structure reduces or prevents the shear deformation ofthe polymer material during impact of a face of a golf club head with agolf ball. The reinforcement structure also reduces or prevents theshear deformation of the polymer material without affecting the normalcompliance behavior of the polymer material during impact of a face of agolf club head with a golf ball thereby resulting in a golf club headwith a greater COR and better durability.

One aspect of the present invention is a wood-type golf club head with amatrix layer disposed on the front wall of a body of the wood-type golfclub head. The matrix layer preferably comprises a reinforcementstructure and a polymer material.

Another aspect of the present invention is an iron-type golf club headwith a matrix layer disposed on the front wall of a body of theiron-type golf club head. The matrix layer preferably comprises areinforcement structure and a polymer material.

Yet another aspect of the present invention is a putter-type golf clubhead with a matrix layer disposed on the front wall of a body of theputter-type golf club head. The matrix layer preferably comprises areinforcement structure and a polymer material.

Having briefly described the present invention, the above and furtherobjects, features and advantages thereof will be recognized by thoseskilled in the pertinent art from the following detailed description ofthe invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a front view of a wood-type golf club head with a matrixlayer.

FIG. 1A is a front view of a wood-type golf club head with analternative matrix layer.

FIG. 1B is a front view of a wood-type golf club head with analternative matrix layer.

FIG. 2 is a front view of a wood-type golf club head illustrating heightand width measurements.

FIG. 3 is a top view of the wood-type golf club head of FIG. 1.

FIG. 4 is a cross-sectional view of the wood-type golf club head of FIG.1 taken along line 4—4 of FIG. 3.

FIG. 4A is a cross-sectional view of an alternative embodiment of awood-type golf club head.

FIG. 5 is an enlarged isolated view of a matrix layer and a front wall.

FIG. 5A is an enlarged isolated view of the alternative embodiment ofFIG. 4A.

FIG. 6 is an enlarged isolated view of a prior art polymer layerdisposed on a front wall of a loft driver to illustrate the sheardeformation during impact with a golf ball.

FIG. 7 is a heel-side view of the wood-type golf club head of FIG. 1.

FIG. 8 is a toe-side view of the wood-type golf club head of FIG. 1.

FIG. 9 is a bottom plan view of the wood-type golf club head of FIG. 1.

FIG. 10 is a bottom perspective view of the wood-type golf club head ofFIG. 1.

FIG. 11 illustrates an alternative embodiment of a matrix layer.

FIG. 12 illustrates an alternative embodiment of a matrix layer.

FIG. 13 is cross-sectional view of an alternative embodiment of awood-type golf club head with a matrix layer.

FIG. 14 is a front view of a putter-type golf club head with a matrixlayer.

FIG. 15 is a toe-side view of the putter-type golf club head of FIG. 14.

FIG. 16 is a rear perspective view of the putter-type golf club head ofFIG. 14.

FIG. 17 is a top plan view of the putter-type golf club head of FIG. 14.

FIG. 18 is a front view of an alternative putter-type golf club headwith a matrix layer.

FIG. 19 is a rear perspective view of the putter-type golf club head ofFIG. 18.

FIG. 20 is a cross-sectional view of the putter-type golf club head ofFIG. 18 along line 20—20.

FIG. 21 is a top plan view of the putter-type golf club head of FIG. 18.

FIG. 22 is a top perspective view of an alternative putter-type golfclub head with a matrix layer.

FIG. 23 is a front plan view of the putter-type golf club head of FIG.22.

FIG. 24 is a top plan view of the putter-type golf club head of FIG. 22.

FIG. 25 is a bottom plan view of the putter-type golf club head of FIG.22.

FIG. 26 is a front plan view of an iron-type golf club head with amatrix layer.

FIG. 27 is a cross-section view of an alternative iron-type golf clubhead with a matrix layer.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1–10, the golf club head of the present invention isgenerally designated 20. The golf club head 20 of FIGS. 1–10 is adriver, however, the golf club head of the present invention mayalternatively be a fairway wood, an iron or a putter. The golf club head20 has a body 22 that is preferably composed of a metal material such astitanium, titanium alloy, or the like, and is most preferably composedof a cast titanium alloy material. The body 22 is preferably cast frommolten metal in a method such as the well-known lost-wax casting method.The metal for casting is preferably titanium or a titanium alloy such as6-4 titanium alloy, alpha-beta titanium alloy or beta titanium alloy forforging, and 6-4 titanium for casting. Alternatively, the body 22 iscomposed of 17-4 steel alloy. Additional methods for manufacturing thebody 22 include forming the body 22 from a flat sheet of metal,super-plastic forming the body 22 from a flat sheet of metal, machiningthe body 22 from a solid block of metal, electrochemical milling thebody from a forged pre-form, casting the body using centrifugal casting,casting the body using levitation casting, and like manufacturingmethods.

The golf club head 20, when designed as a driver, preferably has avolume from 200 cubic centimeters to 600 cubic centimeters, morepreferably from 300 cubic centimeters to 450 cubic centimeters, and mostpreferably from 350 cubic centimeters to 420 cubic centimeters. A golfclub head 20 for a driver with a body 22 composed of a cast titaniumalloy most preferably has a volume of 380 cubic centimeters. The volumeof the golf club head 20 will also vary between fairway woods(preferably ranging from 3-woods to eleven woods) with smaller volumesthan drivers.

The golf club head 20, when designed as a driver, preferably has a massno more than 215 grams, and most preferably a mass of 180 to 215 grams.When the golf club head 20 is designed as a fairway wood, the golf clubhead preferably has a mass of 135 grams to 180 grams, and preferablyfrom 140 grams to 165 grams.

The body 22 has a crown 24, a sole 26, a ribbon 28, and a front wall 30.The body 22 optionally has a recess 32 in the front wall 30. The recess32 preferably has a depth, “Dr”, as shown in FIG. 4, that ranges from0.040 inch to 0.250 inch, more preferably from 0.080 inch to 0.120 inch,and is most preferably 0.100 inch. The body 22 preferably has a hollowinterior 47. The golf club head 20 has a heel end 36, a toe end 38 anaft end 37. A shaft, not shown, is placed within a hosel 49 at the heelend 36. In a preferred embodiment, the hosel 49 is internal to the body22, and the shaft extends to the sole 26.

The golf club head 20 has a matrix layer 40 that is disposed on thefront wall 30 of the body 22. In a preferred embodiment, the matrixlayer 40 is an insert that is disposed in the recess 32 of the frontwall 30. In an alternative embodiment shown in FIG. 13, the matrix layer40 is disposed on the exterior surface of the front wall 30. A moredetailed description of golf club head 20 with a layer disposed on thefront wall is disclosed in U.S. Pat. No. 6,607,451 for A CompliantPolymer Face Golf Club Head, which is hereby incorporated by referencein its entirety. The matrix layer 40 is preferably composed of areinforcement structure 50 and a polymer material 52. As shown in FIG.2, the matrix layer 50 has a width Wm that preferably ranges from 2.0inches to 4.0 inches. In a preferred embodiment, the matrix layer 40 hasan uniform thickness that ranges from 0.040 inch to 0.250 inch, morepreferably a thickness of 0.080 inch to 0.120 inch, and is mostpreferably 0.100 inch.

The polymer material 52 for the matrix layer 50 is preferably athermoplastic polyurethane material. Polymer materials that may beutilized in the matrix layer 50 include: polymers from Bayer Corporationsold under the TEXIN brand such as TEXIN 4215, TEXIN 4210, TEXIN 270,TEXIN 4210 T2, TEXIN 270 T2, TEXIN 4215 T2 and TEXIN 4215 T3, which arethermoplastic polyurethanes and thermoplastic polyurethane andpolycarbonate blends; polymers from BASF corporation such as TERLURANEGP-7, TERLURAN HI-10, TERLURAN GP-22, which are ABS polymers, ULTRAMIDA3HG5, LURANS 778 T1 and LURAN S 778 T/TE T2, which are ABS andpolyamide blends, and TRIAX 1120, which is an ABS and polyamide blend;polymers from Du Pont Chemicals such as HYTREL 7246 thermoplasticpolyester elastomer and HYLENE 58D polymer and SURLYN ionomers; polymersfrom GE Polymers such as NORYL PPX/PPX7115 polyphenylene ether andpolystryene blend, LEXAN EXL 1330 T2, LEXAN EXL 1330 T3, LEXAN ML6143/C1000, LEXAN 1330/ML6143, LEXAN ML6143H and LEXAN 1330, which areamorphous thermoplastic polymers, CYCOLOY C1000HF T1, CYCOLOY C1000HFT2, CYCOLOY C1000HF T3, CYCOLOY C1000HF T4 AND CYCOLOY C1000HF T5, whichare ABS and polycarbonate blends; polymers from Atofina corporation soldunder the brands ATOFINA 3429, ATOFINA 3467 and ATOFINA 7823 MZ;polymers from BP Chemical sold under the brand BAREX 210, which is an Eacrylonitrile-methyl acrylate copolymer; polymers from Chevroncorporation sold under the brands BK-12, KR03 and BK10/NAS90 blend;polymers from Exxon Mobil chemical sold under the brands PP1024E4,PP1043N, PP7033N, PP7032E2T1, PP7032KN and PP7032E2T2; polymers fromHuntsman Chemical sold under the brand IROGRAN 113557; polymers from RTPcorporation sold under the brands 1299-A 80D w/glass, 1299-B 80D withoutglass, RTP 4085 and Nylon 6 with nano; and polymers from Uniroyal soldunder the brand AN2501750 blend T1, AN2501750 blend T2 and LF750D.

The polymer material 52 is preferably injection molded or compressionmolded around the reinforcement structure 50. However, those skilled inthe pertinent art will recognize that other integration methods may beutilized in combining the reinforcement structure 50 and the polymermaterial 52 without departing from the scope and spirit of the presentinvention. The matrix layer 40 is applied to the front wall 30 of thegolf club head 20. One application method is to use an adhesive toadhere an interior surface of the matrix layer 40 to the exteriorsurface of the front wall 30 within the recess 32. Another method is touse compressive forces to apply the matrix layer 40 within the recess32. Yet another method is to use bolts to secure the matrix layer 40within the recess 32. Yet a further method is to form the matrix layer40 within the recess 32. However, those skilled in the pertinent artwill recognize other methods to place the matrix layer 40 on the frontwall 30 of the golf club head 20 without departing from the scope andspirit of the present invention.

The reinforcement structure 50 is preferably composed of aluminum,aramides fiber, fiberglass, carbon or a rigid polyurethane material, andsuch reinforcement structures are available from Hexcel Corporation ofPleasanton, Calif. under the brand HEXCEL COMPOSITES. The reinforcementstructure 50 is preferably a plurality of interconnected cells 51, witheach cell 51 preferably having a cell size ranging from 0.010 inch to0.375 inch, more preferably from 0.0625 inch to 0.125 inch. Each cell 51is preferably formed of integrated walls 53. As shown in FIG. 5, thereinforcement structure 50 preferably has a depth that extends along theentire depth, “Dm”, of the matrix layer 40. In an alternativeembodiment, the reinforcement structure 50 has a depth that partiallyextends along the depth of the matrix layer 40, ranging from 25% to 75%of the depth of the matrix layer 40. As shown in FIG. 5, each of thewalls 53 of the reinforcement structure 50 preferably has a thickness,“Tr”, ranging from 0.0005 inch to 0.01 inch, more preferably from 0.001inch to 0.005 inch, and most preferably 0.002 inch.

In an alternative embodiment shown in FIGS. 4A and 5A, an outer layer 41covers the matrix layer 40. The outer layer 41 provides additionalprotection to the matrix layer 40 during impact with a golf ball. Theouter layer may be composed of any of the previously disclosed polymermaterials. Further, the outer layer 41 preferably has a thicknessranging from 0.005 inch to 0.100 inch. In a most preferred embodiment,the outer layer 41 is composed of the same material as the polymermaterial 52 of the matrix layer 40.

As shown in FIGS. 1A and 1B, alternative embodiments of the matrix layer40 have a reinforcement structure 50 that is only present in a portionof the matrix layer 40. In FIG. 1A, the reinforcement structure is onlydisposed in the center of the face of the golf club head 20 inaccordance with high impact probability locations. In FIG. 1B, thereinforcement structure is absent from the center of the face 45 of thegolf club head 20.

FIGS. 11 and 12 illustrate various grid formations of the reinforcementstructure 50. FIG. 11 has a rectangular grid formation and FIG. 12 has atriangular grid formation. A preferred embodiment has a hexagonal gridformation, as shown in FIG. 1. Those skilled in the pertinent art willrecognize that other grid formations may be used for the reinforcementstructure 50 of the matrix layer 40 without departing from the scope andspirit of the present invention.

As shown in FIG. 6, a lofted driver with a polymer layer 52 a on thefront wall 30 a will experience a shear stress, τ_(o), from the normalstress, σ_(o), due to impact with a golf ball. The shear stress causesshear deformation of the polymer layer 52 a thereby affecting the normalcompliance of the polymer layer 52 a, which reduces the increased CORdue to the polymer layer 52 a. The reinforcement structure 50 of thematrix layer 40 of the present invention reduces or eliminates the sheardeformation of the polymer material 52 thereby allowing for increasedCOR and durability.

The wood-type golf club head 20 preferably has a high coefficient ofrestitution thereby enabling for greater distance of a golf ball hitwith the golf club head of the present invention. The coefficient ofrestitution (also referred to herein as “COR”) is determined by thefollowing equation:

$e = \frac{y_{2} - y_{1}}{U_{1} - U_{2}}$

wherein U₁ is the club head velocity prior to impact; U₂ is the golfball velocity prior to impact which is zero; v₁ is the club headvelocity just after separation of the golf ball from the face of theclub head; v₂ is the golf ball velocity just after separation of thegolf ball from the face of the club head; and e is the coefficient ofrestitution between the golf ball and the club face.

The values of e are limited between zero and 1.0 for systems with noenergy addition. The coefficient of restitution, e, for a material suchas a soft clay or putty would be near zero, while for a perfectlyelastic material, where no energy is lost as a result of deformation,the value of e would be 1.0. The present invention provides a wood-typegolf club head 20 preferably having a coefficient of restitutionpreferably ranging from 0.80 to 0.87, and more preferably from 0.82 to0.86, as measured under standard USGA test conditions.

As shown in FIG. 3, the depth, “D”, of the club head 20 from the frontwall 30 to the aft-end 37 preferably ranges from 3.0 inches to 4.5inches, and is most preferably 3.75 inches. As shown in FIG. 2, theheight, “H”, of the club head 20, as measured while in address position,preferably ranges from 2.0 inches to 3.5 inches, and is most preferably2.50 inches or 2.9 inches. The width, “W”, of the club head 20 from thetoe end 38 to the heel end 36 preferably ranges from 4.0 inches to 5.0inches, and more preferably 4.7 inches.

The face 45 of the golf club head 20 preferably has a large aspectratio. The aspect ratio as used herein is defined as the height, “H”, ofthe face 45 divided by the width, “W”, of the face 45. The width, W, ismeasured between the farthest limits of the face 45 from the heel end 36to the toe end 38. The measured width, W, does not include any portionof the body 22 that may be on the front of the club head 20 but not partof the face 45. The face 45 includes the front wall 30 and matrix layer40. The height, H, is measured from between the farthest limits of theface 45 from the crown 24 to the sole 26. As with the width, W, theheight, H, does not include any portion of the body 22 that may be onthe front of the club head 20 but not part of the face 45.

In one embodiment, the width W is 3.35 inches and the height H is 2.0inches giving an aspect ratio of 0.6. The face 45 of the golf club head20 preferably has an aspect ratio that is greater than 0.575. The aspectratio of the face 45 preferably ranges from 0.575 to 0.8, and is mostpreferably from 0.6 to 0.7. A discussion of the aspect ratio of the faceof a golf club head is disclosed in Kosmatka, U.S. Pat. No. 6,338,683for Striking Plate For A Golf Club Head, which is hereby incorporated byreference in its entirety.

The center of gravity and the moments of inertia of the golf club head20 may be calculated as disclosed in U.S. Pat. No. 6,607,452, entitledHigh Moment Of Inertia Composite Golf Club, and hereby incorporated byreference in its entirety. In general, the moment of inertia, Izz, aboutthe Z axis for the golf club head 20 will preferably range from 2700g-cm² to 4000 g-cm², more preferably from 3000 g-cm² to 3800 g-cm². Themoment of inertia, Iyy, about the Y axis for the golf club head 20 willpreferably range from 1500 g-cm² to 3500 g-cm².

Further, the golf club head 20 preferably has superior products ofinertia wherein at least one of the products inertia, Ixy, Ixz and Iyz,of the golf club head 20 has an absolute value less than 100 g-cm², andmore preferably two or three products of inertia, Ixy, Ixz and Iyz, ofthe golf club head 20 have an absolute value less than 100 g-cm². Adiscussion of the products of inertia is disclosed in Cackett, et al.,U.S. Pat. No. 6,425,832 for Large Volume Driver Head With High MomentsOf Inertia, which is hereby incorporated by reference in its entirety.

As shown FIGS. 14–25, another embodiment of the present invention is aputter-type golf club head 20 with a matrix layer 40 disposed in arecess 32 in a front wall 30 of the body 22 of the putter-type golf clubhead 20.

The putter-type golf club head 20 has a body 22 with a front wall 30with a recess 32 therein. The matrix layer 40 extends along most of thefront wall 30 from a heel end 36 of the putter-type golf club head 20 toa toe end 38 of the putter-type golf club head 20, and from a sole 26 toa crown 24.

The body 22 of the putter-type golf club head 20 is preferably composedof a metallic material such as stainless steel. Other metallic materialsinclude titanium, aluminum, tungsten, zinc, magnesium, and alloys ofstainless steel and tungsten. However, those skilled in the pertinentart will recognize that the body 22 may be composed of other materialswithout departing from the scope and spirit of the present invention.Further, the non-matrix layer portion of the front wall 30 may be smoothor textured to provide a consistent or non-consistent surface.Additionally, the body 22 may be specifically weighted to provide aspecific center of gravity and inertial properties for the putter-typegolf club head 20. In a preferred embodiment, each of the putter-typeclub heads 20 weighs approximately 328 grams±7 grams. Further, in apreferred embodiment, the recess 32 of each of the putter-type clubheads 20 has a depth of approximately 0.205 inches±0.010 inch.

FIGS. 14–17 illustrate a semi-mallet putter-type golf club head 20 andFIGS. 18–21 illustrate a flanged blade putter. A more thoroughdescription of the putter-type golf club heads 20 of FIGS. 14–21 is setforth in U.S. Pat. No. 6,238,302, issued on May 29, 2001, which relevantparts are hereby incorporated by reference. FIGS. 22–25 illustrate anextended mallet type putter-type golf club head 20 with an alignmentsystem such as disclosed in U.S. Pat. No. 6,471,600, issued on Oct. 22,2002, which relevant parts are hereby incorporated by reference.However, those skilled in the art will recognize that other similarputter designs may be utilized without departing from the scope andspirit of the present invention.

As shown FIGS. 26–27, another embodiment of the present invention is aniron-type golf club head 20 with a matrix layer 40 disposed in a recess32 in a front wall 30 of the body 22 of the iron-type golf club head 20,or as shown in FIG. 27, the matrix layer 40 is adhered to the front wall30 of the body 22 of the iron-type golf club head 20. Such an iron-typegolf club head 20 is described in U.S. Pat. No. 5,704,849, issued onJan. 6, 1998, and which relevant parts are hereby incorporated byreference.

As shown in FIG. 26, the iron-type golf club head (wedge) 20 has a body22 with a front wall 30 with a recess 32 therein. The matrix layer 40 isdisposed within the recess 32 and preferably extends along most of thefront wall 30 from a heel end 36 of the iron-type golf club head 20 to atoe end 38 of the iron-type golf club head 20, and from a sole 26 to acrown (top wall) 24.

From the foregoing it is believed that those skilled in the pertinentart will recognize the meritorious advancement of this invention andwill readily understand that while the present invention has beendescribed in association with a preferred embodiment thereof, and otherembodiments illustrated in the accompanying drawings, numerous changes,modifications and substitutions of equivalents may be made thereinwithout departing from the spirit and scope of this invention which isintended to be unlimited by the foregoing except as may appear in thefollowing appended claims. Therefore, the embodiments of the inventionin which an exclusive property or privilege is claimed are defined inthe following appended claims.

1. A wood-type golf club head comprising: a body composed of a metallicmaterial and including a front wall having a recess formed thereinhaving a depth of 0.100 inch, the front wall having an exterior surface,the body having a volume ranging from 300 cubic centimeters to 600 cubiccentimeters; and a matrix layer having an interior surface and anexterior surface, the matrix layer disposed within the recess of thefront wall with the interior surface of the matrix layer disposed on theexterior surface of the front wall, the matrix layer having a thicknessof 0.100 inch, the matrix layer comprising a reinforcement structurehaving a plurality of walls forming a plurality of cells, thereinforcement structure composed of an aluminum material and having adepth that extends from 25% to 75% of the depth of the matrix layer, anda polymer material substantially filling each of the plurality of cellsof the reinforcement structure, the polymer material composed of athermoplastic polyester elastomer; wherein the reinforcement structureis absent from the center of the face; wherein the golf cub head has acoefficient of restitution ranging from 0.80 to 0.87 and a mass rangingfrom 180 grams to 215 grams.
 2. The wood-type golf club head accordingto claim 1 wherein the golf club head has a moment of inertia, Izz,about the Z axis through the center of gravity of the golf club headthat ranges from 2700 g-cm² to 4000 g-cm².